Virginia health officials are seeing more cases of antibiotic-resistant staph infection.

They blame the increase on a combination of genetic changes in the bacteria and the fact that there are more medical treatments that weaken the body and allow the germs to invade. State epidemiologist Dr. Carl Armstrong said in a briefing Friday that an emergency order by the governor this week directing state labs to report severe cases will help health officials track the incidence and specific number of infections.

He says severe cases involve MRSA being found in the blood and organs that don't normally contain bacteria. Many people normally carry staph on their skin without any symptoms, but people can be infected through a cut or other opening in the skin.

He said staph usually turns up in hospitals.

State officials said Friday they couldn't confirm that a Bedford County high school student's death was caused by community-acquired MRSA.

The Virginia Department of Health is asking school districts to report clusters of three or more cases, not individual infections.